* blockframe.c (frameless_look_for_prologue):

	* blockframe.c (frameless_look_for_prologue):
	Add FUNCTION_START_OFFSET only if func_start is non-zero.
	* minsyms.c (lookup_minimal_symbol_by_pc):  Return NULL if
	pc is not in a known section.
	* stack.c (print_frame_info):  Remove check for fi->pc in known
	section, now handled by lookup_minimal_symbol_by_pc.